1. Field of the Invention
The present invention relates to rear view mirror systems for vehicles.
2. Prior Art
A wide variety of periscope type or external rear view mirrors have been advanced for use in vehicles. An example is the patent issued to Moultrie, U.S. Pat. No. 3,043,195 which does show a convex lens, a pair of perpendicular exposed front surface lenses, a ground glass screen and a concave viewing mirror. The apparatus is rather complex and involves a large number of optical components.
U.S. Pat. No. 1,905,323 issued to Wallace, shows a rear view attachment that utilizes a conventional planar front mirror adjacent the driver, and a convex mirror mounted at the rear upper corner in the interior of the vehicle so that the driver can get a view of things that are adjacent to the ground immediately to the rear of the vehicle.
Kovach U.S. Pat. No. 2,757,575 shows a prism that has three optical elements for viewing, and it should be noted that prisms of the type shown in Kovach do cause some distortion, are bulky and generally expensive, and further the device requires installation through the roof of the car which requires cutting a hole.
U.S. Pat. No. 3,001,449 issued to Hyde shows an optical system for a rear view mirror arrangement and does show a curved mirror but requires elements having definite focal length lens in the system, as well as a cylindrical mirror which compliments the focal length of the lens, producing one-to-one telescope arrangement.
There are also patents which provide for viewing through the windshield of a car in a rear view mirror system such as Ewing, U.S. Pat. No. 2,346,739.
There are therefore a number of multiple mirror, rear view mirror systems for vehicles, none of which will provide a relatively distortion-free viewing utilizing two elements only, and without relying on lenses or prisms.